Roton and phonon linewidths in superfluid 4HeT. Keller1, 2, K. Habicht3, 4, R. Golub4 and F. Mezei4
1 Max-Planck-Institute for Solid State Research - D-70569 Stuttgart, Germany
2 FRM-2 - D-85747 Garching, Germany
3 TU Darmstadt, Institut für Festkörperphysik - D-64289 Darmstadt, Germany
4 Hahn-Meitner-Institut, BENSC - D-14109 Berlin, Germany
(Received 5 March 2004; accepted in final form 25 June 2004)
We present high-resolution data of the energy widths of elementary excitations in superfluid on the phonon branch 0.3Å -1 < Q< 0.6 Å -1 and both the energies and the widths on the roton branch 1.93Å -1<Q<2.6Å -1 at T=0.98 . In both Q-regions a broadening of is clearly observed. The roton energies and group velocities observed in the present experiment are significantly smaller than those reported from previous experiments.
61.12.Ex - Neutron scattering (including small-angle scattering).
67.40.Db - Quantum statistical theory; ground state, elementary excitations.
© EDP Sciences 2004